The present invention relates to a high-temperature method of removing sulfur containing gases from gaseous fuel mixtures particularly those provided for high-temperature fuel cell use. The invention particularly relates to the use of highly dispersed copper on zinc oxide to remove hydrogen sulfide from fuel gas at elevated temperatures. Previous methods for removing sulfur containing gases from fuel gases have included such low temperature techniques as scrubbing with liquid solutions containing alkaline minerals, or organic bases or alcohols. Such processes may be operated at low temperatures of 100.degree.-150.degree. C. or even at subambient temperatures. Therefore, these method are of considerable disadvantage for use in combination with high-temperature fuel cells such as molten carbonate or solid oxide fuel cells that operate at several hundred to over a thousand degrees Celsius.
Prior high-temperature bulk sorbents involving various oxides such as the lathanide oxides, oxides of iron and oxides of zinc have in some instances proven dissappointing in their performance and/or their regenerability. Iron oxides have been used typically as a first stage sorbent, removing H.sub.2 S down to a level of about 200 ppm.
Therefore, it is an object of the present invention to provide a method of removing sulfur containing gases from high-temperature fuel gases using a sorbent with improved sulfur containing capacity.
It is a further object to provide a method involving the use of a highly dispersed sulfur sorbent material on a support also capable of sulfur removal from a fuel gas.
It is a further object to provide a regenerable solid sorbent material capable of removing hydrogen sulfide gas from a fuel gas mixture at temperatures compatable with high-temperature fuel cell use.